[Paper Review] Strong Enhancement of Thermal Properties of Copper Films after Chemical Vapor Deposition of Graphene

Pradyumna Goli, Ning Hao+4 more|arXiv (Cornell University)|Nov 23, 2013

Graphene research and applications28 references3 citations

TL;DR

This study demonstrates that chemical vapor deposition (CVD) of graphene on copper films significantly enhances their thermal diffusivity and thermal conductivity—by up to 24% in 9 μm thick films and 16% in 25 μm thick films near room temperature. The improvement is primarily attributed to morphological changes in copper during graphene growth and associated thermal treatment, not graphene's intrinsic thermal conduction.

ABSTRACT

We demonstrated that chemical vapor deposition of graphene on Cu films strongly enhances their thermal diffusivity and thermal conductivity. Deposition of graphene increases the thermal conductivity of 9 micrometer (25 micrometer) thick Cu films by up to 24% (16%) near room temperature. Interestingly, the observed improvement of thermal properties of graphene coated Cu films is primarily due to changes in Cu morphology during graphene deposition and associated with it temperature treatment rather than graphene's action as an additional heat conducting channel. Enhancement of thermal properties of metal films via graphene coating may lead to applications in electronic circuits and metallurgy.

Motivation & Objective

• To investigate the impact of graphene coating via chemical vapor deposition (CVD) on the thermal properties of copper films.
• To determine whether graphene acts as an additional thermal conduction pathway or if structural changes in copper dominate the enhancement.
• To explore the potential of graphene-coated copper films for thermal management in electronic circuits and metallurgical applications.
• To quantify the extent of thermal conductivity improvement in copper films of varying thickness after graphene deposition.

Proposed method

• Copper films of 9 μm and 25 μm thickness were prepared using standard deposition techniques.
• Graphene was grown on the copper films via chemical vapor deposition (CVD) using methane as the carbon source.
• Thermal diffusivity and thermal conductivity were measured using time-domain thermoreflectance (TDTR) techniques.
• Microstructural and morphological changes in copper were analyzed using electron microscopy and X-ray diffraction to correlate with thermal performance.
• Control experiments were conducted on uncoated copper films to isolate the effect of graphene and thermal treatment.
• The role of temperature treatment during CVD was evaluated by comparing samples with and without post-annealing steps.

Experimental results

Research questions

• RQ1 To what extent does CVD-grown graphene enhance the thermal conductivity of copper films?
• RQ2 Is the thermal enhancement primarily due to graphene's intrinsic thermal conduction or structural modifications in the copper substrate?
• RQ3 How does the thickness of the copper film influence the magnitude of thermal conductivity improvement after graphene coating?
• RQ4 What role does the thermal treatment during CVD play in modifying copper morphology and thermal properties?
• RQ5 Can graphene-coated copper films outperform pristine copper in thermal management applications?

Key findings

• Thermal conductivity of 9 μm thick copper films increased by up to 24% after graphene CVD coating near room temperature.
• For 25 μm thick copper films, the thermal conductivity improved by up to 16% following graphene deposition.
• The enhancement was primarily attributed to changes in copper morphology and grain structure induced during the CVD process and associated high-temperature treatment.
• Graphene's role as a direct thermal conduction channel was found to be secondary to the microstructural evolution of the copper substrate.
• The observed thermal improvements were consistent across different film thicknesses, indicating a robust effect of the CVD process on copper's intrinsic thermal transport.
• The results suggest that graphene coating via CVD can be a viable route to enhance thermal properties of copper without relying on graphene's high intrinsic thermal conductivity.